Among the many effects of climate change, altered disturbance regimes may offer the most direct route for large-scale and long-lasting transformation of landscapes. In western forests, wildfires are burning larger areas and causing more tree mortality, with subsequent regeneration often containing altered plant communities. For wildlife species, persisting in and navigating through these fire-transformed landscapes is critical if populations are to avoid local extirpation, but the change in fire regimes may alter how easy it is to persist. For many species, ecologists do not know what features of post-burn landscapes enable animals to use the burned area, nor how quickly post-fire habitat conditions become suitable. We have addressed such questions via systematic reviews of studies examining responses of mammals to forest fires, plus field-based research on snowshoe hares, Canada lynx, and marten. In the field, we have used snow-tracking, abundance estimators, and radio-collar data to examine how these species move through or around burned areas.
Results/Conclusions
Ecologists lack a comprehensive understanding of how wildlife species respond to fire. Our recent review of the small mammal – fire literature signals that most such studies address stand-scale patterns in species presence or abundance, rather than examining behaviour or landscape-scale effects. In contrast, studies on ungulates and carnivores in burned landscapes tend to focus on single species, measure browse offtake, or examine behaviour of individual animals across multiple habitat types. Our fieldwork on snowshoe hares, Canada lynx, and marten shows that these animals respond strongly to fire size, fire severity, residual structure, and rapidity of shrub and tree regeneration. Fire age is a weak predictor of use by these species, largely because post-fire heterogeneity is not well predicted by time-since-fire, but the animals respond directly to the available vegetation or downed woody debris. Collectively, our reviews and our field data suggest that maintaining populations of mammals in burned landscapes will hinge on spatial configuration of burned and unburned stands and the post-burn heterogeneity. Current fire management often encourages complete burn-out or post-fire salvage logging, both of which reduce post-fire heterogeneity and delay tree regeneration. Our data suggest wildlife species may be resilient to post-burn landscapes provided substantial post-fire heterogeneity is retained.